I wrote a screensaver for the nbody application. You can manually install it and try it from here: http://milkyway.cs.rpi.edu/milkyway/download/nbody_0.92/ (available for Linux, Windows and OS X 64 bit. OS X requires 10.7 Lion). It requires OpenGL 3.2 so it needs a DirectX 10 class GPU (Something newer than Radeon HD 2xxx or GeForce 8000 series)

The screensaver has various mouse and keyboard controls for viewing the simulations. A list of all controls can be accessed by pressing the h or ? keys. You can manipulate the camera by dragging with the mouse and zooming with the scroll wheel.

There are a couple of known problems which you may run into:

- For workunits with larger timesteps, it seems very jumpy. There's an option to update at some interval instead of at every opportunity. There is another option to stop the simulation to wait for the graphics, so that every timestep is drawn as a frame and the animation is smooth.
- The orbit trace view will not do what you expect except when using the option to stop the simulation for the graphics
- The optional axes are ugly
- The preference descriptions aren't very good

I added a bunch of preferences to the web project preferences, but they're not quite finished yet (e.g. the default values don't show up in the boxes when you don't have them set).

Looks like the graphics application has the wrong filename for what the app_info.xml references: it's "milkyway_nbody_graphics_0.92_windows_x86_64.exe" but should be "milkyway_nbody_graphics_0.92_windows_x86_64__mt.exe" (i.e. add __mt at the end). With that I don't get any errors in BOINC, but I haven't gotten any tasks yet.

<stderrgfx.txt>
Failed to connect to shared scene
Failed to connect to shared scene
Failed to connect to shared scene
Failed to connect to shared scene
Failed to connect to shared scene
Could not attach to simulation after 5 attempts

Beautiful.
But I have a special idea for NBody simulation: Could You please create a special nbody runs which would calculate "gravivational moon-like" forces on Earth during end of 2012 - crossing the Galactic Equator? Because they might be so strong that lots of volcanoes would erupt and could bring new ICE AGE.
I think Mankind should try to determine IF these (forces) will be so strong to do that.

It could help Humanity to eventually start to prepare for the change. (i.e. finish development of Thermo-nuclear reactor! Or Tesla's GeoMagn. dynamo. "Free energy"), because in THIS CASE - we would need lots of energy to generate some "sunlight" to grow most kinds of food...Melwen - Child of the Fangorn Forest
Rig "BRISINGR" [ASUS G73-JH, i7 720QM 1.73, 4x2GB DDR3 1333 CL7, ATi HD5870M 1GB GDDR5],bought on 2011-02-24

1. Needs more continuity. Since the WU's that are available finish for my computer in a mere 30 seconds, the graphics can only run for... 30 seconds. After that, the screensaver just stops (or rather, just stops progressing and hangs). It still functions, but it does not continue over to the next WU. In fact, when you quit the screensaver to look at the graphics for the next one that is already running, the screensaver fails to load (with the error being that it cannot attach to a running process, being the application itself) until the next WU arrives and runs.

Could there be a way for the screensaver to identify when the WU finishes, stay on, and then reattach to the next WU that runs?

2. Needs more... fluidity. When I watched your demo, the particle motion seemed rather fluid and smooth. In contrast, when I viewed the same from my end, it was quite jumpy.. or rather, it just updated whenever it felt like. IN fact, i dont think it updated per .001 Gyr (as it did in the demo). It just updated all over the place, and it was slow at updating. I did not notice a regular interval. is this something that can be fixed? it would look much better if it acted the way your demo had it.

3. a little thing, but the fact that you couldn't pause the screen from rotating annoyed me. could you add an option to enable and disable screen rotation? I would really like to see the particles move on their own instead of seeing it happen while flying around ;)

Nice screensaver, but I do have some suggestions for future builds:
[quote]1. Needs more continuity. Since the WU's that are available finish for my computer in a mere 30 seconds, the graphics can only run for... 30 seconds. After that, the screensaver just stops (or rather, just stops progressing and hangs). It still functions, but it does not continue over to the next WU. In fact, when you quit the screensaver to look at the graphics for the next one that is already running, the screensaver fails to load (with the error being that it cannot attach to a running process, being the application itself) until the next WU arrives and runs.

Could there be a way for the screensaver to identify when the WU finishes, stay on, and then reattach to the next WU that runs?

I wasn't really sure what it should do when the workunit finishes

2. Needs more... fluidity. When I watched your demo, the particle motion seemed rather fluid and smooth. In contrast, when I viewed the same from my end, it was quite jumpy.. or rather, it just updated whenever it felt like. IN fact, i dont think it updated per .001 Gyr (as it did in the demo). It just updated all over the place, and it was slow at updating. I did not notice a regular interval. is this something that can be fixed? it would look much better if it acted the way your demo had it.

This is one of the problems I mentioned. The way it runs now it just updates the display whenever it can and lets' the actual simulation go ahead on its own. The demo video made the simulation stop so that everything is smooth. Another option which I might make the default just updates the displayed scene every 10 seconds or so jumping to the current view.

3. a little thing, but the fact that you couldn't pause the screen from rotating annoyed me. could you add an option to enable and disable screen rotation? I would really like to see the particles move on their own instead of seeing it happen while flying around ;)

There already is, it (and all the other on/off preferences) aren't enabled in the web preferences yet.

Failed to connect to shared scene
Failed to connect to shared scene
Failed to connect to shared scene
Failed to connect to shared scene
Failed to connect to shared scene
Could not attach to simulation after 5 attempts

Looks like the graphics application has the wrong filename for what the app_info.xml references: it's "milkyway_nbody_graphics_0.92_windows_x86_64.exe" but should be "milkyway_nbody_graphics_0.92_windows_x86_64__mt.exe" (i.e. add __mt at the end). With that I don't get any errors in BOINC, but I haven't gotten any tasks yet.

Then I have some WU. But still have a problems. This WU didn't run. =(

@Alexone:
I had the same issue. For me, i fixed it in the appinfo.xml file. What i did was search for the number 8 (as the app is defaulted to use up to 8 cores, but for some reason doesn't run UNLESS 8 cores are present) and replace that 8 with however many cores your CPU has/however many you want the app to use up. After that the app will run again ;)

Please, is it possible to create WUs in the future with approx. 10 times more calc.operations in each one?

Or maybe to send those more complicated only to 4+ cores clients? :) That would surely balance and optimize the effectivity:crunching-time / idleCPU-manage-only-timeratio.

I loose about 10 percent of the CPU time on project-managing actions (sending old WU and downloading new WU) + some time before the new WU is fully loaded and READY (2 seconds or so! ) in RAM and finally really starts crunching! And thats a lot CPU time wasted especially when combined with the now-needed managing time.

Please, try to: Either fix the bug with limit of 1 task per computer or create 10 times greater work units, so the manage-time will be only a small percentage in the whole process.
Thanx :-)

That can not be the problem as the machines I use for MW are all 64Bit.
I don't get them somehow.

Try to reset the project (If You have low estimated time already, You may have run into "my favourite" bug of "LIMIT 1 task" + if you have one or more ghost WU(s)..., you can never get more work than that one ghost).

And If You install the 0.92 x64 binaries again,
oh!Did You rename the file to "milkyway_nbody_graphics_0.92_windows_x86_64__mt.exe" as suggested above?
*Namaste* Filip